Hydrogen peroxide (H₂O₂) is considered one of the most important chemical products and has a promising future in photocatalytic preparation, which is green, pollution-free, and hardly consumes any non-renewable energy. This study involves the preparation of benzoxazine with Si─O bonds via the Mannich reaction, followed by co-hydrolysis to produce photocatalysts containing benzoxazine with Si─O─Ti bonds. In this study, a benzoxazine photocatalyst with Si─O─Ti bonds is synthesized and characterized using fourier transform infrared spectroscopy, nuclear magnetic resonance, and X-ray photoelectron spectroscopy. The size and elemental distribution of the nanoparticles are confirmed by transmission electron microscopy and scanning electron microscopy. The photocatalytic synthesis of H₂O₂ is tested using the titanium salt detection method, and the rate is found to be 7.28 µmol h⁻¹. Additionally, the catalyst exhibits good hydrolysis resistance and could be reused multiple times. The use of benzoxazine with Si─O─Ti bonds presents a promising experimental and theoretical foundation for the industrial production of H₂O₂ through photocatalytic synthesis.